JPH0562790A - X-ray ct device - Google Patents

Abstract

PURPOSE:To uniformly grasp the correct exchange timing of an X-ray tubular bulb without requiring a skill and prevent the overlooking of the exchange timing and the exchange at the too early timing. CONSTITUTION:Integrating and storing means (2a, 4, 5, 7a, 8) measuring the exposed X-ray dosage and integrating and storing the measured X-ray dosage and comparing and reporting means (6, 8) comparing the integrated value of the means and the allowable integrated dosage value of the X-ray tubular bulb 1 in use, generating an alarm sound when both of them are made equal, and invariably displaying the number of remaining operable days and the number of remaining scannable times are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray CT apparatus having a function of notifying information regarding the replacement time of an X-ray tube.

[0002]

2. Description of the Related Art In a conventional apparatus, replacement of an X-ray tube is
It is often performed empirically based on the number of scans (scan frequency), usage period, usage status, etc., and is easily influenced by the degree of experience of service personnel during maintenance. There is also one that displays the number of scans by the scan counter, but this shows the total number of scans from the start of operation of the currently used X-ray tube to the present, and the tube voltage and tube current at the time of scanning. It is not taken into consideration that the above is not necessarily constant. For this reason, the replacement time may be overlooked and the X-ray tube may fail at an unexpected time, or the replacement time may be too early and the X-ray tube may be wasted. This is also the case when the standard of replacement is changed from the number of scans to the usage period or usage status, and it is very difficult to know the exact replacement time.

Further, in the case of continuous scanning by slip ring CT, one scan (a series of scans over a plurality of times) can be used for taking a few tens of normal scans. It is more and more difficult to know the exact replacement time.

[0004]

As described above, in the conventional apparatus, the grasp of the replacement time varies depending on the difference in the experience of the service personnel, so that the accurate replacement timing can be grasped uniformly regardless of the experience of the service personnel. It was very difficult. Further, the factor that determines the replacement time of the X-ray tube is only ambiguous such as the number of scans. Even when the number of scans or the period of use is the same, the remaining number of scans and the period of use that can be used vary depending on the tube voltage, the tube current, and the scan time. For this reason, there is a problem that the X-ray tube may fail at an unexpected time when it is overlooked, or that the X-ray tube is wasted because the replacement time is too early.

An object of the present invention is to make it possible to quantitatively know the replacement time of an X-ray tube, to make it possible to grasp a uniform and accurate replacement time regardless of the experience of a service technician. It is an object of the present invention to provide an X-ray CT apparatus capable of preventing an X-ray tube failure at an unexpected time and a replacement of a usable X-ray tube due to an early replacement time.

[0006]

The above-mentioned object is to measure an X-ray dose and to integrate and store the measured X-ray dose, and to add and store the integrated value and the X-ray in use. This is achieved by comparing the allowable integrated dose values of the tubes to obtain information on the replacement time of the X-ray tube, and providing a comparison / informing means for informing this.

Here, as a means for measuring the X-ray dose, there is a method of obtaining the actual X-ray exposure. This is a method of obtaining the dose for one scan from the row data (row data of the reference channel portion of the X-ray detector) obtained by normal scan measurement. As another method, there is a method of calculating from the product of the tube voltage, the tube current and the scan time. As a means for accumulating and storing the measured X-ray dose, there is a method using a CPU and an auxiliary storage device. The information regarding the replacement time of the X-ray tube includes information indicating whether the accumulated value up to the present exceeds the allowable accumulated dose value of the X-ray tube, and the allowable accumulated dose of the X-ray tube. There is information indicating the remaining number of scannable days and the number of remaining days that can be operated based on the difference and the average amount of use up to that point after subtracting the current integrated value from the value. As means for notifying this information, when the integrated value exceeds the allowable integrated dose value of the X-ray tube, a method of notifying it with an alarm sound,
There is a method of displaying the number of remaining scans and the number of remaining days of operation on a monitor or panel.

[0008]

In the accumulating and storing means, the total amount of daily exposure X-ray dose is calculated, and the total amount is also integrated with the X-ray dose converted so as to be the total under the same exposure condition. ,Remember. On the other hand, the comparison / informing means compares the integrated value stored in the integrating / storing means with the allowable integrated dose value obtained in advance for the X-ray tube currently in use. And
Information indicating whether or not the cumulative value to date exceeds the allowable cumulative dose value, the current cumulative value is subtracted from the allowable cumulative dose value, and the difference and the average usage amount up to that point are also included. Then, information indicating the number of remaining scannable days and the number of remaining operable days (information regarding the replacement time of the X-ray tube) is notified. As a result, the correct replacement time can be grasped uniformly regardless of the experience of the service personnel, and oversight of the replacement time or replacement too early is prevented.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an X-ray CT apparatus according to the present invention. In FIG. 1, 1 is an X-ray tube, 2 is an X-ray detector, which are arranged on a rotating plate (not shown) so as to face each other, and form the main configuration of the scanner 3. 2a
Is a reference channel of the X-ray detector 2. Reference numeral 4 is a preamplifier that amplifies the output signal of the X-ray detector 2, and is provided in the scanner 3. An image processing device 5 reconstructs an image by the signal from the preamplifier 4. Reference numeral 6 denotes a display device for notifying a reconstructed image and information about the time to replace the X-ray tube, which will be described later. Reference numeral 7 denotes a magnetic disk device in which a program and parameters for image reconstruction calculation are stored. In the present invention, the X-ray dose of the X-ray tube 1 currently used from the start of operation to the present The integrated value is also stored. Reference numeral 7a denotes a storage area (X-ray dose integrated value storage area). Reference numeral 8 is a CPU that controls the above-mentioned units and performs various calculations, and 9 is a subject.

The X-ray detector 2 (reference channel 2a), the preamplifier 4, the image processing device 5, the magnetic disk device 7 (X-ray dose integrated value storage area 7a) and the CPU 8 are exposed to X. It also constitutes an integrating and storing means for measuring the X-ray dose and integrating and storing the measured X-ray dose. Further, the display device 6 and the CPU 8 obtain information about the replacement time of the X-ray tube 1 by comparing the integrated value by the integration and storage means and the allowable integrated dose value of the X-ray tube 1 in use. It also constitutes a comparison and reporting means for reporting.

Next, the operation of the apparatus of the present invention will be described with reference to FIG. 2 as well. Since the normal measurement operation of the X-ray CT apparatus is the same as that of the conventional apparatus, the X-ray exposure is performed here. The description is centered on the operation from the time when the information regarding the replacement time of the X-ray tube is notified. That is, X
The X-rays emitted from the X-ray tube 1 pass through the subject 9 and become X-rays.
It is incident on the line detector 2. In a normal scan, various corrections are performed using the X-ray data that has passed through the subject 9 and is attenuated to reconstruct an image.

As the X-ray dose to be integrated when determining the replacement time of the X-ray tube 1, the X-ray absorption coefficient differs depending on the subject 9 in the transmitted X-ray dose, and therefore different under the same measurement conditions. Do not use this as it will be a value. Therefore, as the X-ray dose data used for the integration, the X-ray dose data of the reference channel 2a of the X-ray detector 2 that is not related to the subject 9 is used. This data becomes row data in the image processing device 5 via the preamplifier 4 like the data of the other measurement channels of the X-ray detector 2. After this, the row data of the measurement channel is used for image reconstruction, but the row data of the reference channel 2a portion is not directly involved in the image reconstruction itself.

After the image reconstruction, the raw data is stored in the X-ray dose integrated value storage area 7a of the magnetic disk device 7 together with the reconstructed image by the CPU 8. At that time, all the row data of the reference channel 2a portion is taken out and added. If the averaging is performed by angle addition when the X-ray data is acquired, the total number of samples is corrected (addition number times). Then, for each scan (X-ray exposure), the integrated value of the X-ray dose up to that time is read from the storage area 7a of the magnetic disk device 7, and the X-ray dose of this time is set so as to be a value under the same measurement condition. Convert dose values and add (step 2
01-204).

Thereafter, an allowable integrated dose value (preliminarily obtained by a durability test or the like and set and stored in the magnetic disk device 7) corresponding to the type of the X-ray tube 1 currently in use is set. Read from (step 205),
This allowable integrated dose value and the addition result (X
Then, the remaining dose (= allowable cumulative dose value-X-ray dose cumulative value) is calculated (step 206).
Since the addition result is the X-ray dose integrated value used at the next exposure, the storage area 7a of the magnetic disk device 7 is
(Step 207).

For the remaining dose determined, X until the previous day
By dividing the integrated dose of the radiation dose by the number of operating days of the X-ray tube 1 and dividing by the average daily use dose, the remaining number of days available for operation can be obtained. Further, if the integrated value of the X-ray dose up to the previous exposure is divided by the number of scans (the number of exposures) of the X-ray tube 1 up to that time, the remaining scannable number is obtained. These calculations are carried out by the CPU 8, and the remaining workable days and the remaining scannable times, which are the calculation results, are displayed on the display device 6 (step 206).

In the above embodiment, the actual measurement value was used for measuring the X-ray dose, but the set X-ray exposure conditions (tube voltage,
A value obtained by calculation using the CPU 8 from the tube current and the scan time) may be used. Further, in the above-described embodiment, as the information regarding the notification time of the replacement of the X-ray tube, the operation remaining days and the scan remaining number are described as an example. However, for the allowable integrated dose value of the X-ray tube, It may be information indicating whether or not the X-ray dose integrated value up to the present has exceeded. In this case, since the notification is an alternative, it is possible to easily notify the operator or the service person by an alarm sound or LED light emission without using the display device 6. Also, a combination of both may be used.

[0017]

As described above, according to the present invention, X
Since the X-ray dose integrated value is used as a criterion for determining the replacement time of the X-ray tube, it becomes possible to quantitatively know the replacement time, and therefore it is possible to uniformly and accurately grasp the replacement time regardless of the experience of the service personnel. There is an effect that it is possible to prevent an X-ray tube failure at an unexpected time due to oversight of the replacement time and replacement of a usable X-ray tube due to the replacement time being too early.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a device of the present invention.

FIG. 2 is a flowchart of the same device.

[Explanation of symbols]

 1 X-ray tube 2 X-ray detector 2a Reference channel 3 Scanner 4 Preamplifier 5 Image processing device 6 Display device 7 Magnetic disk device 7a X-ray dose integrated value storage area 8 CPU 9 Subject

Claims (1)

[Claims] Claims: 1. An X-ray dose is measured, and an integration and storage means for integrating and storing the measured X-ray dose, an integration value by this integration and storage means, and an allowable integration dose value of an X-ray tube in use are displayed. An X-ray CT apparatus comprising: comparison and notification means for comparing and obtaining information regarding the replacement time of the X-ray tube.